And I'm Robert Siegel. President Obama is asking Congress for an extra billion dollars. It's for defense, to reassure nervous allies and let Eastern Europe that United States is committed to their security. The president spoke to an audience in Poland today. He said the U.S. commitment is especially important in the face of Russia's actions in neighboring Ukraine.

CORNISH: Poland is the starting point in the president's four-day visit to Europe. It coincides with a historic milestone. 25 years ago this week, Poland held its first partially free elections as the country began to emerge from Soviet domination. NPR's Scott Horsley reports from Warsaw.

SCOTT HORSLEY, BYLINE: Air Force One always makes an impression, when it lands on foreign soil. But this morning, it was other planes that commanded most of the attention, four F-16s parked in a hangar just off the runway at Warsaw's Chopin Airport. The United States sent additional fighter jets to Poland after Russian troops took control in nearby Crimea. Obama met with some of the airmen who fly and services jets and called part of the backbone of the Polish-American alliance.

PRESIDENT BARACK OBAMA: I'm starting the visit here because our commitment to Poland's security, as well as the security of our allies in Central and Eastern Europe, is a cornerstone of our own security. And it is sacrosanct.

HORSLEY: Later, at a joint news conference with Polish President Bronislaw Komorowski, Obama said he hopes more military help will soon be on the way. He's asking lawmakers for $1 billion to fund what the White House is calling the European Reassurance Initiative.

OBAMA: Under this effort, and with the support of Congress, the United States will preposition more equipment in Europe. We will be expanding our exercises and training with allies to increase the readiness of our forces.

HORSLEY: By bolstering Europe's military defenses, Obama hopes to supplement the economic sanctions, that have so far been the West's main response to Russia's moves in Ukraine. Obama's also talking with Europeans about diversifying their energy supplies, so Russia can't so easily wield its gas and oil exports as a weapon. Beefing up Europe's defenses won't come cheap, though. And Obama says the United States can't do it alone.

OBAMA: We have seen a decline, steadily, in European defense spending generally. There are exceptions like Poland, like Estonia. But for the most part, we have seen a steady decline. That has to change.

HORSLEY: Poland has promised to increase its defense budget, which was already relatively robust. Komorowski welcomed the additional American military help, suggesting, through an interpreter, the F in F-16 stands not only for fighter jet but freedom.

PRESIDENT BRONISLAW KOMOROWSKI: (Through translator) We are absolutely convinced that this is a good response. And it is important for the whole region, not only for Poland. It is an important response that will be analyzed as a very important element of discouragement for Russia to continue the policy of pressure and aggression against the neighbors that are located to the east of our borders.

HORSLEY: Poland is not the only country that's been rattled by events in Ukraine. This afternoon, Obama tried to offer similar reassurance to nine other presidents from countries throughout Eastern and Central Europe. Those leaders met in the Polish Presidential Palace, where the Warsaw Pact was signed nearly 60 years ago. Today, instead of enlisting in the Russian orbit, the leaders are trying to stay out of it. Tomorrow Obama joins Poland is celebrating 25 years of freedom from Soviet domination. He points to Poland's subsequent economic progress as a hopeful model for neighboring Ukraine.

OBAMA: As Ukrainians undertake the hard work of political and economic reform, Poland's going to have an important role to play in sharing some of the lessons of its own success.

HORSLEY: Obama also meets tomorrow with the incoming president of Ukraine, Petro Poroshenko. And later this week, old allies and adversaries will mark another milestone of European liberation, the 70th anniversary of D-Day. Scott Horsley, NPR News, Warsaw. Transcript provided by NPR, Copyright NPR.